Added kind operator

pkg/yqlib/operator_kind.go

@@ -0,0 +1,39 @@
+package yqlib
+
+import (
+	"container/list"
+
+	yaml "gopkg.in/yaml.v3"
+)
+
+func kindToText(kind yaml.Kind) string {
+	switch kind {
+	case yaml.MappingNode:
+		return "map"
+	case yaml.SequenceNode:
+		return "seq"
+	case yaml.DocumentNode:
+		return "doc"
+	case yaml.ScalarNode:
+		return "scalar"
+	case yaml.AliasNode:
+		return "alias"
+	default:
+		return "unknown"
+	}
+}
+
+func getKindOperator(d *dataTreeNavigator, context Context, expressionNode *ExpressionNode) (Context, error) {
+	log.Debugf("GetKindOperator")
+
+	var results = list.New()
+
+	for el := context.MatchingNodes.Front(); el != nil; el = el.Next() {
+		candidate := el.Value.(*CandidateNode)
+		node := &yaml.Node{Kind: yaml.ScalarNode, Value: kindToText(candidate.Node.Kind), Tag: "!!str"}
+		result := candidate.CreateReplacement(node)
+		results.PushBack(result)
+	}
+
+	return context.ChildContext(results), nil
+}